Factor the expression:
8x3 + 4x2 - 2x - 1


(2x + 1)(2x + 1)(2x - 1)
(2x + 1)(2x - 1)(2x - 1)
(4x + 1)(x - 1)(2x + 1)
(4x + 1)(x + 1)(2x - 1)